Sweet's syndrome is characterized by the abrupt onset of fever, neutrophilic leukocytosis, and erythematous, tender pseudovesiculated plaques or nodules that respond readily to corticosteroid therapy. It is usually distinguished by the presence of mature neutrophils on histopathologic examination. We describe a 38-year-old man with acute myelogenous leukemia who had an erythematous vesicular eruption of the left eye develop that resembled cellulitis. A biopsy specimen revealed a dermal infiltrate of mature neutrophils and immature myeloblastic precursors. He later had hemorrhagic pseudovesiculated plaques develop bilaterally on his hands. A biopsy specimen again revealed abundant neutrophils with immature forms. A similar eruption developed at the site of a Hickman catheter placement 4 months later. His skin lesions responded rapidly to oral corticosteroids. This case is unique in that his initial presentation of Sweet's syndrome resembled orbital cellulitis that was characterized by immature myeloid precursors on histopathology. (J Am Acad Dermatol 2001;45:590-5.)